> ## Documentation Index
> Fetch the complete documentation index at: https://help.experro.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

Field Settings, Catalog Settings, and Algorithm are the three configuration surfaces that control how Experro Discovery indexes your catalog and decides which products to surface on every search and category page.

## The Three Configuration Surfaces

<CardGroup cols={3}>
  <Card title="Algorithm" href="/experro_discovery/search/algorithm_field_settings_catalog_settings/quick_decision_guide">
    The ranking layer. One or more named algorithms scoped to specific searches or categories, each with five configuration tabs covering relevance (including the search engine choice), performance, personalization, newness, and ranking behavior.
  </Card>

  <Card title="Field Settings" href="/experro_discovery/search/algorithm_field_settings_catalog_settings/field_settings">
    The per-field configuration layer. For each indexed field, you define its type, how it participates in search and faceting, how Experro's natural language processing layer treats it, and whether it carries internal-only data.
  </Card>

  <Card title="Catalog Settings" href="/experro_discovery/search/algorithm_field_settings_catalog_settings/catalog_settings">
    The catalog-wide configuration layer. Settings that apply across every product, including Gen AI vector indexing, the field used for precision and personalization, out-of-stock handling, color grouping, and variant slicing attributes.
  </Card>
</CardGroup>

## How They Relate

The three surfaces build on one another, from shaping the raw data to ranking the final results:

* **Field Settings shapes the data** — it defines what each field is and how it can be used.
* **Catalog Settings tunes catalog-wide behavior** on top of that data.
* **Algorithm decides how the resulting indexed catalog is ranked** for any given query.

<Note>
  Changes to Field Settings or to certain Catalog Settings options require a catalog re-index before they take effect. Algorithm changes apply immediately on save and activate.
</Note>